Question

当我运行rake db：migrate时，我得到以下输出：

== 20141219011612 CreatePost：迁移=======================================    - create_table（＆＃34;帖子＆＃34;）rake中止了！ StandardError：发生错误，此以及所有后续迁移都已取消：   == 20141219011612帖子：迁移=======================================    - create_table（＆＃34;帖子＆＃34;）rake中止了！ StandardError：发生错误，此以及所有后续迁移都已取消：

PG :: DuplicateTable：错误：关系＆＃34;帖子＆＃34;已存在：CREATE   表＆＃34;帖子＆＃34; （＆＃34; id＆＃34;序列主键，＆＃34;帖子＆＃34;文字，＆＃34; release_date＆＃34;   时间戳，＆＃34; created_at＆＃34;时间戳，＆＃34; updated_at＆＃34;时间戳）   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in   async_exec' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in阻止执行＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract_adapter.rb:373:in block in log' /home/admin/.rvm/gems/ruby-2.1.5/gems/activesupport-4.1.8/lib/active_support/notifications/instrumenter.rb:20:in instrument＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract_adapter.rb:367:in log' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:127:in执行＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/schema_statements.rb:205:in   method_missing＆＃39;中的create_table' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:649:in阻止   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:621:in   block in say_with_time' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:621:in say_with_time＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:641:in   method_missing' /home/admin/Desktop/postr/db/migrate/20141219011612_post_posts.rb:3:in起来＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:598:in   exec_migration' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:579:in阻止（2级）迁移＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:578:in   block in migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in with_connection＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:577:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:752:in迁移＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:991:in   ddl_transaction中的block in execute_migration_in_transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:1037:in阻止＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   block in transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:209:in within_new_transaction＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/transactions.rb:208:in交易＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:1037:in   ddl_transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:990:in execute_migration_in_transaction＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:952:in   block in migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:948:in各＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:948:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:807:in起来＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:785:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/railties/databases.rake:34:in阻止（2级）＆＃39; ActiveRecord的:: StatementInvalid：   PG :: DuplicateTable：错误：关系＆＃34;帖子＆＃34;已存在：CREATE   表＆＃34;帖子＆＃34; （＆＃34; id＆＃34;序列主键，＆＃34;帖子＆＃34;文字，＆＃34; release_date＆＃34;   时间戳，＆＃34; created_at＆＃34;时间戳，＆＃34; updated_at＆＃34;时间戳）   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in   async_exec' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in阻止执行＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract_adapter.rb:373:in block in log' /home/admin/.rvm/gems/ruby-2.1.5/gems/activesupport-4.1.8/lib/active_support/notifications/instrumenter.rb:20:in instrument＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract_adapter.rb:367:in log' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:127:in执行＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/schema_statements.rb:205:in   method_missing＆＃39;中的create_table' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:649:in阻止   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:621:in   block in say_with_time' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:621:in say_with_time＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:641:in   method_missing' /home/admin/Desktop/postr/db/migrate/20141219011612_post_posts.rb:3:in起来＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:598:in   exec_migration' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:579:in阻止（2级）迁移＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:578:in   block in migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in with_connection＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:577:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:752:in迁移＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:991:in   ddl_transaction中的block in execute_migration_in_transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:1037:in阻止＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   block in transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:209:in within_new_transaction＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/transactions.rb:208:in交易＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:1037:in   ddl_transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:990:in execute_migration_in_transaction＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:952:in   block in migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:948:in各＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:948:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:807:in起来＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:785:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/railties/databases.rake:34:in阻止（2级）＆＃39; PG :: DuplicateTable：错误：   关系＆＃34;帖子＆＃34;已经存在   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in   async_exec' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in阻止执行＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract_adapter.rb:373:in block in log' /home/admin/.rvm/gems/ruby-2.1.5/gems/activesupport-4.1.8/lib/active_support/notifications/instrumenter.rb:20:in instrument＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract_adapter.rb:367:in log' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:127:in执行＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/schema_statements.rb:205:in   method_missing＆＃39;中的create_table' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:649:in阻止   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:621:in   block in say_with_time' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:621:in say_with_time＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:641:in   method_missing' /home/admin/Desktop/postr/db/migrate/20141219011612_post_posts.rb:3:in起来＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:598:in   exec_migration' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:579:in阻止（2级）迁移＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:578:in   block in migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in with_connection＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:577:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:752:in迁移＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:991:in   ddl_transaction中的block in execute_migration_in_transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:1037:in阻止＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   block in transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:209:in within_new_transaction＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/transactions.rb:208:in交易＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:1037:in   ddl_transaction' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:990:in execute_migration_in_transaction＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:952:in   block in migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:948:in各＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:948:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:807:in起来＆＃39;   /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/migration.rb:785:in   migrate' /home/admin/.rvm/gems/ruby-2.1.5/gems/activerecord-4.1.8/lib/active_record/railties/databases.rake:34:in阻止（2级）＆＃39;任务：TOP =＆gt; db：migrate（参见   使用--trace运行任务完全跟踪

我不知道如何做到这一点，因为在计划文件中我没有邮寄表格。

Answer 1

不知何故，您最终在数据库中找到了一个名为“posts”的表。也许是从您之前的迁移中删除而没有回滚？如果您不关心数据库中的任何数据，可以运行

rake db:drop db:create db:migrate

使您的开发数据库与您当前的迁移一致。

如果您不希望丢失其他表中的数据，请打开数据库控制台并手动删除posts表：

$ rails db

# drop table posts;

然后再次运行db:migrate。

Answer 2

检查db / schema.rb

除了db / migrate / [timestamp]中的迁移之外，你很可能在那里创建了相同的表your_migration

你可以删除db / migrate / [timestamp] your_migration，如果它与模式中找到的一样重复，它应该可以工作。

Answer 3

如果这有助于其他任何人，我意识到我一直在使用在使用MySQL时生成的schema.rb文件。转换到Postgres之后，我忘记了在使用rake db:migrate之前我需要运行rake db:schema:load

Answer 4

我发现的一个hack是在迁移文件上创建表之前先撬开。

require 'pry'
binding.pry

create_table :your_table_name

并删除该表：

drop_table :your_table_name

之后，您可以删除drop_table行，它将正常工作！

Answer 5

杀死当前的postgres程序：

sudo kill -9 `ps -u postgres -o pid`

再次启动postgres：

brew services start postgres

删除，创建和迁移表：

rails db:drop db:create db:migrate

Answer 6

对于以上没有得到您答案的人

就我而言，一个月前我一直在从事一项功能，而该字段恰巧是在那时创建的。现在，当我尝试运行迁移rake db: migrate时，我看到了此错误。我知道并且肯定不会由于任何错误而出现在这里。

我还尝试回滚该特定迁移

rake db:migrate:down VERSION=20200526083835

但是由于某种原因，它什么也没做，进一步，我不得不注释掉该迁移文件中的up方法。

# frozen_string_literal: true

class AddColToAccounts < ActiveRecord::Migration
  def up
    # execute 'commit;'
    #
    # add_column :accounts, :col, :boolean,
    #            null: false,
    #            default: false
    

  end

  def down
    execute 'commit;'

    remove_column :accounts, :col
    
  end
end

而且，现在我可以运行迁移了。

最后，我撤消了评论，然后完成了。

谢谢

PG :: DuplicateTable：错误

6 个答案: